Hays County Sheriff Gary Cutler announced Friday that his deputies had arrested former Hays County Sheriff’s Office employee Hilary Cook and charged her with Official Oppression and Violation of Civil Rights/Person in Custody.

Late Friday night, a 47-year-old mother aimed a handgun at her 19-year-old son and demanded he leave her Kyle home. During the struggle that followed, authorities say the gun fired, delivering a fatal shot to her son’s...